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1424 jermar 1
/*
2071 jermar 2
 * Copyright (c) 2006 Jakub Jermar
1424 jermar 3
 * All rights reserved.
4
 *
5
 * Redistribution and use in source and binary forms, with or without
6
 * modification, are permitted provided that the following conditions
7
 * are met:
8
 *
9
 * - Redistributions of source code must retain the above copyright
10
 *   notice, this list of conditions and the following disclaimer.
11
 * - Redistributions in binary form must reproduce the above copyright
12
 *   notice, this list of conditions and the following disclaimer in the
13
 *   documentation and/or other materials provided with the distribution.
14
 * - The name of the author may not be used to endorse or promote products
15
 *   derived from this software without specific prior written permission.
16
 *
17
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
 */
28
 
1757 jermar 29
/** @addtogroup genericmm
1702 cejka 30
 * @{
31
 */
32
 
1424 jermar 33
/**
1702 cejka 34
 * @file
1424 jermar 35
 * @brief   Backend for address space areas backed by an ELF image.
36
 */
37
 
2000 decky 38
#include <lib/elf.h>
1424 jermar 39
#include <debug.h>
40
#include <arch/types.h>
41
#include <mm/as.h>
42
#include <mm/frame.h>
43
#include <mm/slab.h>
1426 jermar 44
#include <mm/page.h>
45
#include <genarch/mm/page_pt.h>
46
#include <genarch/mm/page_ht.h>
1424 jermar 47
#include <align.h>
48
#include <memstr.h>
49
#include <macros.h>
50
#include <arch.h>
51
 
2076 jermar 52
#ifdef CONFIG_VIRT_IDX_DCACHE
53
#include <arch/mm/cache.h>
54
#endif
55
 
1780 jermar 56
static int elf_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access);
57
static void elf_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame);
1426 jermar 58
static void elf_share(as_area_t *area);
1424 jermar 59
 
60
mem_backend_t elf_backend = {
61
    .page_fault = elf_page_fault,
62
    .frame_free = elf_frame_free,
1426 jermar 63
    .share = elf_share
1424 jermar 64
};
65
 
66
/** Service a page fault in the ELF backend address space area.
67
 *
68
 * The address space area and page tables must be already locked.
69
 *
70
 * @param area Pointer to the address space area.
71
 * @param addr Faulting virtual address.
72
 * @param access Access mode that caused the fault (i.e. read/write/exec).
73
 *
2132 jermar 74
 * @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e.
75
 *     serviced).
1424 jermar 76
 */
1780 jermar 77
int elf_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access)
1424 jermar 78
{
1425 jermar 79
    elf_header_t *elf = area->backend_data.elf;
80
    elf_segment_header_t *entry = area->backend_data.segment;
1426 jermar 81
    btree_node_t *leaf;
3007 jermar 82
    uintptr_t base, frame, page, start_anon;
1424 jermar 83
    index_t i;
2134 jermar 84
    bool dirty = false;
1424 jermar 85
 
86
    if (!as_area_check_access(area, access))
87
        return AS_PF_FAULT;
88
 
3007 jermar 89
    ASSERT((addr >= ALIGN_DOWN(entry->p_vaddr, PAGE_SIZE)) &&
2132 jermar 90
        (addr < entry->p_vaddr + entry->p_memsz));
3007 jermar 91
    i = (addr - ALIGN_DOWN(entry->p_vaddr, PAGE_SIZE)) >> PAGE_WIDTH;
92
    base = (uintptr_t)
93
        (((void *) elf) + ALIGN_DOWN(entry->p_offset, PAGE_SIZE));
1426 jermar 94
 
3007 jermar 95
    /* Virtual address of faulting page*/
96
    page = ALIGN_DOWN(addr, PAGE_SIZE);
97
 
98
    /* Virtual address of the end of initialized part of segment */
99
    start_anon = entry->p_vaddr + entry->p_filesz;
100
 
1426 jermar 101
    if (area->sh_info) {
102
        bool found = false;
103
 
104
        /*
105
         * The address space area is shared.
106
         */
3007 jermar 107
 
1426 jermar 108
        mutex_lock(&area->sh_info->lock);
1780 jermar 109
        frame = (uintptr_t) btree_search(&area->sh_info->pagemap,
3007 jermar 110
            page - area->base, &leaf);
1426 jermar 111
        if (!frame) {
2745 decky 112
            unsigned int i;
1426 jermar 113
 
114
            /*
115
             * Workaround for valid NULL address.
116
             */
117
 
118
            for (i = 0; i < leaf->keys; i++) {
3007 jermar 119
                if (leaf->key[i] == page) {
1426 jermar 120
                    found = true;
121
                    break;
122
                }
123
            }
124
        }
125
        if (frame || found) {
1546 jermar 126
            frame_reference_add(ADDR2PFN(frame));
2132 jermar 127
            page_mapping_insert(AS, addr, frame,
128
                as_area_get_flags(area));
3007 jermar 129
            if (!used_space_insert(area, page, 1))
1426 jermar 130
                panic("Could not insert used space.\n");
131
            mutex_unlock(&area->sh_info->lock);
132
            return AS_PF_OK;
133
        }
134
    }
3007 jermar 135
 
1426 jermar 136
    /*
2132 jermar 137
     * The area is either not shared or the pagemap does not contain the
138
     * mapping.
1426 jermar 139
     */
3007 jermar 140
    if (page >= entry->p_vaddr && page + PAGE_SIZE <= start_anon) {
1424 jermar 141
        /*
142
         * Initialized portion of the segment. The memory is backed
143
         * directly by the content of the ELF image. Pages are
144
         * only copied if the segment is writable so that there
145
         * can be more instantions of the same memory ELF image
146
         * used at a time. Note that this could be later done
147
         * as COW.
148
         */
149
        if (entry->p_flags & PF_W) {
1780 jermar 150
            frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
2132 jermar 151
            memcpy((void *) PA2KA(frame),
152
                (void *) (base + i * FRAME_SIZE), FRAME_SIZE);
2134 jermar 153
            dirty = true;
1424 jermar 154
        } else {
3007 jermar 155
            frame = KA2PA(base + i * FRAME_SIZE);
1424 jermar 156
        }  
3007 jermar 157
    } else if (page >= start_anon) {
1424 jermar 158
        /*
159
         * This is the uninitialized portion of the segment.
160
         * It is not physically present in the ELF image.
161
         * To resolve the situation, a frame must be allocated
162
         * and cleared.
163
         */
1780 jermar 164
        frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
1424 jermar 165
        memsetb(PA2KA(frame), FRAME_SIZE, 0);
2134 jermar 166
        dirty = true;
1424 jermar 167
    } else {
3007 jermar 168
        size_t pad_lo, pad_hi;
1424 jermar 169
        /*
170
         * The mixed case.
3007 jermar 171
         *
172
         * The middle part is backed by the ELF image and
173
         * the lower and upper parts are anonymous memory.
174
         * (The segment can be and often is shorter than 1 page).
1424 jermar 175
         */
3007 jermar 176
        if (page < entry->p_vaddr)
177
            pad_lo = entry->p_vaddr - page;
178
        else
179
            pad_lo = 0;
180
 
181
        if (start_anon < page + PAGE_SIZE)
182
            pad_hi = page + PAGE_SIZE - start_anon;
183
        else
184
            pad_hi = 0;
185
 
1780 jermar 186
        frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
3007 jermar 187
        memcpy((void *) (PA2KA(frame) + pad_lo),
188
            (void *) (base + i * FRAME_SIZE + pad_lo),
189
            FRAME_SIZE - pad_lo - pad_hi);
190
        memsetb(PA2KA(frame), pad_lo, 0);
191
        memsetb(PA2KA(frame) + FRAME_SIZE - pad_hi, pad_hi, 0);
2134 jermar 192
        dirty = true;
3007 jermar 193
    }
1426 jermar 194
 
3007 jermar 195
    if (dirty && area->sh_info) {
196
        frame_reference_add(ADDR2PFN(frame));
197
        btree_insert(&area->sh_info->pagemap, page - area->base,
198
            (void *) frame, leaf);
199
    }
1426 jermar 200
 
201
    if (area->sh_info)
202
        mutex_unlock(&area->sh_info->lock);
3007 jermar 203
 
1424 jermar 204
    page_mapping_insert(AS, addr, frame, as_area_get_flags(area));
3007 jermar 205
    if (!used_space_insert(area, page, 1))
1426 jermar 206
        panic("Could not insert used space.\n");
1424 jermar 207
 
208
    return AS_PF_OK;
209
}
210
 
211
/** Free a frame that is backed by the ELF backend.
212
 *
213
 * The address space area and page tables must be already locked.
214
 *
215
 * @param area Pointer to the address space area.
216
 * @param page Page that is mapped to frame. Must be aligned to PAGE_SIZE.
217
 * @param frame Frame to be released.
218
 *
219
 */
1780 jermar 220
void elf_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame)
1424 jermar 221
{
1425 jermar 222
    elf_header_t *elf = area->backend_data.elf;
223
    elf_segment_header_t *entry = area->backend_data.segment;
3007 jermar 224
    uintptr_t base, start_anon;
1424 jermar 225
    index_t i;
3007 jermar 226
 
227
    ASSERT((page >= ALIGN_DOWN(entry->p_vaddr, PAGE_SIZE)) &&
2132 jermar 228
        (page < entry->p_vaddr + entry->p_memsz));
3007 jermar 229
    i = (page - ALIGN_DOWN(entry->p_vaddr, PAGE_SIZE)) >> PAGE_WIDTH;
230
    base = (uintptr_t) (((void *) elf) +
231
        ALIGN_DOWN(entry->p_offset, FRAME_SIZE));
232
    start_anon = entry->p_vaddr + entry->p_filesz;
233
 
234
    if (page >= entry->p_vaddr && page + PAGE_SIZE <= start_anon) {
1424 jermar 235
        if (entry->p_flags & PF_W) {
236
            /*
2132 jermar 237
             * Free the frame with the copy of writable segment
238
             * data.
1424 jermar 239
             */
1760 palkovsky 240
            frame_free(frame);
1424 jermar 241
        }
242
    } else {
243
        /*
2132 jermar 244
         * The frame is either anonymous memory or the mixed case (i.e.
245
         * lower part is backed by the ELF image and the upper is
246
         * anonymous). In any case, a frame needs to be freed.
2134 jermar 247
         */
248
        frame_free(frame);
1424 jermar 249
    }
250
}
1426 jermar 251
 
252
/** Share ELF image backed address space area.
253
 *
254
 * If the area is writable, then all mapped pages are duplicated in the pagemap.
255
 * Otherwise only portions of the area that are not backed by the ELF image
256
 * are put into the pagemap.
257
 *
258
 * The address space and address space area must be locked prior to the call.
259
 *
260
 * @param area Address space area.
261
 */
262
void elf_share(as_area_t *area)
263
{
264
    elf_segment_header_t *entry = area->backend_data.segment;
265
    link_t *cur;
266
    btree_node_t *leaf, *node;
1780 jermar 267
    uintptr_t start_anon = entry->p_vaddr + entry->p_filesz;
1426 jermar 268
 
269
    /*
270
     * Find the node in which to start linear search.
271
     */
272
    if (area->flags & AS_AREA_WRITE) {
2132 jermar 273
        node = list_get_instance(area->used_space.leaf_head.next,
274
            btree_node_t, leaf_link);
1426 jermar 275
    } else {
276
        (void) btree_search(&area->sh_info->pagemap, start_anon, &leaf);
2132 jermar 277
        node = btree_leaf_node_left_neighbour(&area->sh_info->pagemap,
278
            leaf);
1426 jermar 279
        if (!node)
280
            node = leaf;
281
    }
282
 
283
    /*
284
     * Copy used anonymous portions of the area to sh_info's page map.
285
     */
286
    mutex_lock(&area->sh_info->lock);
2132 jermar 287
    for (cur = &node->leaf_link; cur != &area->used_space.leaf_head;
288
        cur = cur->next) {
2745 decky 289
        unsigned int i;
1426 jermar 290
 
291
        node = list_get_instance(cur, btree_node_t, leaf_link);
292
 
293
        for (i = 0; i < node->keys; i++) {
1780 jermar 294
            uintptr_t base = node->key[i];
1426 jermar 295
            count_t count = (count_t) node->value[i];
2745 decky 296
            unsigned int j;
1426 jermar 297
 
298
            /*
299
             * Skip read-only areas of used space that are backed
300
             * by the ELF image.
301
             */
302
            if (!(area->flags & AS_AREA_WRITE))
3007 jermar 303
                if (base >= entry->p_vaddr &&
304
                    base + count * PAGE_SIZE <= start_anon)
1426 jermar 305
                    continue;
306
 
307
            for (j = 0; j < count; j++) {
308
                pte_t *pte;
309
 
310
                /*
2132 jermar 311
                 * Skip read-only pages that are backed by the
312
                 * ELF image.
1426 jermar 313
                 */
314
                if (!(area->flags & AS_AREA_WRITE))
3007 jermar 315
                    if (base >= entry->p_vaddr &&
316
                        base + (j + 1) * PAGE_SIZE <=
2132 jermar 317
                        start_anon)
1426 jermar 318
                        continue;
319
 
320
                page_table_lock(area->as, false);
2132 jermar 321
                pte = page_mapping_find(area->as,
322
                    base + j * PAGE_SIZE);
323
                ASSERT(pte && PTE_VALID(pte) &&
324
                    PTE_PRESENT(pte));
325
                btree_insert(&area->sh_info->pagemap,
326
                    (base + j * PAGE_SIZE) - area->base,
2467 jermar 327
                    (void *) PTE_GET_FRAME(pte), NULL);
1426 jermar 328
                page_table_unlock(area->as, false);
2132 jermar 329
 
330
                pfn_t pfn = ADDR2PFN(PTE_GET_FRAME(pte));
331
                frame_reference_add(pfn);
1426 jermar 332
            }
333
 
334
        }
335
    }
336
    mutex_unlock(&area->sh_info->lock);
337
}
1702 cejka 338
 
1757 jermar 339
/** @}
1702 cejka 340
 */